408 Life and Immortality. 



conditions that are essential to the life of the species or con- 

 ducive to its extension. But notwithstanding the difficulties 

 in the way, we are able in many cases to deduce completely 

 trustworthy conclusions concerning the climate of a given 

 geological period by an examination of its fossil remains. 

 In Eocene times, or at the beginning of the Tertiary Period, 

 the climate of what is now Western Europe was of a tropical 

 or sub-tropical character, the Eocene beds being found to 

 contain the remains of cowries and volutes, such shells as 

 now inhabit tropical seas, together with the fruits of palms 

 and remains of other tropical plants. And further, it has 

 been shown that in Miocene times, or about the middle of 

 the same epoch, the central parts of Europe were peopled 

 with a luxuriant flora resembling that of the warmer parts 

 of the United States, and that Greenland, now buried for the 

 most part beneath a vast ice-shroud, was warm enough to 

 support a large number of trees, shrubs and other plants 

 that are at present denizens of the temperate regions of the 

 globe. 



And lastly, from the study of fossils, geologists first learned 

 to comprehend a fact, that is, that the crust of the earth is 

 liable to local elevations and subsidences, which may be 

 regarded as of cardinal importance in all modern geological 

 theories and speculations. Long after the remains of shells 

 and those of other marine animals were first observed in the 

 solid rocks constituting the dry land, and at great elevations 

 above the sea-level, attempts were made to explain this 

 unintelligible phenomenon upon the hypothesis that these 

 remains or fossils were mere lusus natures, due to some 

 " plastic virtue latent in the earth." But the common-sense 

 of science soon rejected this idea, and it was universally 

 agreed that these bodies were really the relics of animals 

 that once lived in the sea. When once this was admitted, 

 further steps in the right way of thinking became compara- 

 tively easy, and at the present day no geological doctrine 

 stands -on a surer foundation than that which teaches that 



